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"Suppose a hollow cube to be filled with some fluid (water or steam) at a given pressure, and to have an opening in one side that can readily be closed. The arrangement is such that when the outlet is opened, the internal pressure will remain the same. If the outlet is opened, the fluid will rush out, and if the jet is supposed to strike against a board free to move, the jet will exert a force upon the board tending to swing it in the direction of the jet." —Derr, 1911

Apparatus for Measuring Jet Stream of Steam

"Suppose a hollow cube to be filled with some fluid (water or steam) at a given pressure, and to have…